1. Technical Field of the Invention
In general, this invention relates to an efficient method of describing a physical surface and rapidly localizing an object within a sector of the physical surface. More particularly, this general method is applied to describe the surface of an airport and locate an object within a sector of the airport surface.
To control ground traffic at an airport, an air traffic controller needs to have a map of the airport surface and the ability to track any traffic on the ground. This invention aids the air traffic controller in efficiently locating an aircraft within a sector of the airport surface. For example, this invention permits an air traffic controller to determine whether an aircraft has entered an active runway sector.
2. Description of Related Art
Accidents involving aircraft and ground vehicles and aircraft ground collisions can occur at busy airports. More than three times as many near accidents occur on the ground as in the air. In one such accident, an aircraft strayed onto the wrong runway and was struck by a second aircraft, resulting in the loss of life. In another accident, two aircraft collided when one aircraft was cleared to land on an occupied runway. Continuous situation monitoring in fog, snow, at night, and under other adverse conditions, can cause fatigue in human controllers which may lead to a collision between objects on airport surfaces.
Medium-range airport surveillance radar, such as the Automated Radar Terminal System (ARTS) is good for detecting and tracking many aircraft within a large volume of airspace. However, such systems do not provide adequate surveillance coverage for ground-resident objects, including aircraft that are in the taxiing, holding (stopped), takeoff or landing phases of their flight profiles.
Airport Surface Detection Equipment (ASDE) systems can provide high-resolution, short-range, clutter-free, surveillance information on aircraft and ground vehicles, both moving and fixed, located on or near the surface of airport movement and holding areas under all weather and visibility conditions. An ASDE system formats incoming surface detection radar information for a desired coverage area, and presents it to local and ground controllers on high-resolution, bright displays in the airport control tower cab.
In addition, a large, busy airport is an environment having a vast number of possible conflict situations. In such a dynamic environment, the potential for collision between any given aircraft and any one of possibly many ground-residents, and nearby airborne objects may not be recognized until it is too late to avoid the collision. Also, the occurrence of a conflict in one area of the airport may draw controllers' attention away from evolving conflict situations in other areas of the airport.
Such a demanding and potentially hazardous environment demands rapid and efficient localization of objects on the airport surface. In the past, the air traffic controller was forced to manually identify the airport sector containing each object on the ASDE radar so as to resolve potential incursions between the objects on the airport surface. Increasing airport traffic and, in general, an increase on the demands placed on air traffic controllers has made manual object localization techniques obsolete and potentially dangerous.
Thus, there is a need for an automatic method of describing the airport surface such that an object may be rapidly and efficiently localized within a sector of the airport surface.